1977 Johnson 2HP Outboards Service Manual, Page 29Get this manual
4- hasten the collapse, condenser in the primary circuit absorbs the current which would otherwise arc across the opening breaker pointsThe rapid collapse induces current of sufficient voltage in the secondary circuit to arc across the spark plug air gapThe condenser, which acts like storage tank, consists of thin sheets of metal foil separated insulation, rolled to save space and enclosed in metal caseOne sheet of foil is grounded to the case, the other is connected through an insulated wire to the insulated stationary breaker pointSPARK PLUGS Spark plugs having the proper heat range are very important for peak operation of the motorSpark plugs are classified according to the temperatures at which they are designed to operate, or See Figure 4-2Selection of the correct spark plug depends the type of service to which it is subjectedUnless the spark plug is properly suited to the motor, trouble arise which might interpreted as carburetor difficultyVery low trolling speeds will tend to foul plugs due to the not burning from the coreHowever, at full throttle with hotter plug, the operating temperature too high, resulting in preignitionAn extreme temperature range wiH difficult to control with one plugSpark plugs furnished with the motor are selected for average serviceSee Section 2, SpecificationsFigure Condenser Exploded RUBBER IN5UL ATORIN5ULATION